1. Technical Field
The present invention relates to a method of preparing graphene nanoribbons and a sensor including the same. More particularly, the present invention relates to a method of manufacturing large-area graphene nanoribbons having no residual layer by interposing a chromium layer between a resist layer and a graphene layer, and a sensor including the same.
2. Description of the Related Art
Hydrogen is a future energy source widely utilized in industry and academia. However, hydrogen is colorless and odorless and has high ignitability, and thus requires safe handling. Thus, there has been demand for studies on a sensor as a safeguard. Although earlier studies were focused on metal oxide-based sensors, these sensors could operate at a high temperature of 400° C. or higher. Accordingly, studies on sensors based on rare earth metals such as palladium or platinum have been conducted. Although the rare earth metal-based sensors can operate at room temperature, the sensors have a thick structure when prepared using original bulk materials, and thus exhibit poor properties in terms of sensitivity and response speed. Thus, researchers sought to utilize nanostructured palladium or platinum, which led to development of 1D palladium or platinum nanowire sensors having a considerable potential in terms of sensitivity and response speed. Nowadays, researchers' attention is focused on use of OD nanoparticles. In this case, there is a need for a new material capable of providing a wide and stable area in which the nanoparticles can be electrically connected to one another and well dispersed. For this purpose, graphene, which has recently been developed, are considered as a proper material.
However, when typical CVD graphene or graphene oxides grown via chemical vapor deposition (CVD) allowing a large-area processing are used as a base layer for rare earth metals, there is a problem of reduction in response speed. Thus, there is demand for small graphene. In addition, from the viewpoint of sensor applications, it is required that nanostructures be regularly distributed in an aligned manner and that graphene have no foreign materials left on surfaces thereof, which otherwise could disturb hydrogen sensing reaction of rare earth metals. Thus, there is a need for fine pattering using lithography.
However, despite using any existing lithography techniques for graphene patterning, there is still a problem in that photoresists having been used in patterning remain in a thick layer on surfaces of graphene. That is to say, in graphene patterning with lithography, photoresists have to be spin-coated directly onto the surfaces of graphene, and thus there is actually no way to easily remove photoresist after a lithography process. Although heat treatment at high temperature has been employed to remove photoresists, this process can cause defects in graphene and is time consuming and expensive.